Streptococcus agalactiae
Key points
- This is a severe, systemic infection affecting newborn infants, caused by group B streptococcus.
- This form of infection is caused by group B streptococcus Streptococcus agalactiae, a bacterium which is commonly found in the human gastrointestinal (GI) and genitourinary tracts.
- Expectations (prognosis) This disease can be fatal without early treatment.
- Calling your health care provider This disease is usually diagnosed shortly after birth (from birth to seven days), usually while the baby is still in the hospital.
Alternative names
Group B streptococcal septicemia of the newborn; Sepsis of the newborn; Lancefield group B streptococcus; Group B streptococcus
Definition
This is a severe, systemic infection affecting newborn infants, caused by group B streptococcus.
Causes, incidence, and risk factors
This form of infection is caused by group B streptococcus Streptococcus agalactiae, a bacterium which is commonly found in the human gastrointestinal (GI) and genitourinary tracts.
Early onset of the disease occurs from birth to 6 days of life, generally in the first 24 hours. Late onset of the disease is generally seen in newborns from 7 days to 3 months of age, with most cases occurring in babies around 1 month old.
Group B streptococcus was formerly responsible for about three-fourths of sepsis (overwhelming infection of the blood and organs) cases in infants. However, this has decreased since the institution of screening and treatment of pregnant women at risk.
Risk factors include a mother who is known to have group B streptococcus in her GI or genitourinary tracts, rupture of membranes more than 18 hours prior to delivery, prematurity (less than 37 weeks), and maternal fever during labor.
Group B streptococcus may infect the fetus by traveling from the mother's bloodstream through the placenta or through ruptured membranes as the infant passes through the birth canal. The infant may also become infected after delivery, but this produces a later appearance of illness.
Symptoms
- unstable temperature (low or high)
- poor feeding
- appears unwell, stressed, or anxious
- breathing difficulties
o grunting
o flaring of the nostrils
o rapid breathing (tachypnea)
o short periods without breathing (apneic episodes - see apnea)
o blue appearance (cyanosis) - rapid heart rate (tachycardia) or extremely slow heart rate (bradycardia)
- irregular heartbeat (arrhythmia)
- lethargy
- coma
- shock
Signs and tests
- blood culture (grows group B strep)
- CSF culture (cerebrospinal fluid - from a spinal tap)
- urine culture (see urine collection - infants)
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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